'use strict';

function average_to_letter(collection) {
  let sum=0;
  for(let i=0;i<collection.length;i++){
    sum=sum+collection[i];
  }
  let average=Math.ceil(sum/(collection.length));   //向上取整
  let result=String.fromCharCode(96+average);
  return result;
}
module.exports = average_to_letter;

